Piston mechanism of a lotion pump

ABSTRACT

The present invention provides an improved piston mechanism of a lotion pump. A piston is assembled in the piston cylinder of the lotion pump in a sliding state. The piston contacts the inner wall of the piston cylinder through a ring surface. At least two circular ribs are arranged at intervals on the ring surface, enabling sliding contact between each circular rib and the inner wall of the piston cylinder. Since the circular rib is made of ribs with predefined heights, the contact area may not expand greatly, thus maintaining the smooth sliding of the piston, leading to higher durability and improved applicability of the lotion pump.

CROSS-REFERENCE TO RELATED U.S. APPLICATIONS

Not applicable.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

NAMES OF PARTIES TO A JOINT RESEARCH AGREEMENT

Not applicable.

REFERENCE TO AN APPENDIX SUBMITTED ON COMPACT DISC

Not applicable.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to a lotion pump, and more particularly to an innovative lotion pump with an improved piston mechanism.

2. Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 37 CFR 1.98.

The operating principle of a typical prior art lotion pump is that the pressure head is pressed down and springs up while coupled with a piston rod. A piston moves up and down in the piston cylinder to absorb lotion in collaboration with a check valve at the bottom of the piston cylinder.

The structure of the piston is crucial to the performance of lotion pump, since the air-tightness of the piston and other parts is a major influential factor for suction efficiency and stability.

The piston mechanism of a prior art lotion pump is shown in FIGS. 1 and 2, wherein the axial cross-section wall 11 of piston 10 has a “V”-shaped pattern, such that the upper and lower pyramidal portions 12 are tightly adapted to the inner wall 14 of the piston cylinder 13 for frictional sliding.

The following shortcomings are found in actual application of the prior art.

Given the fact of slide contact between the “V”-shaped axial cross-section wall 11 of the piston 10 and the inner wall 14 of the piston cylinder 13, the piston 10 could move smoothly due to the smaller friction area between the pyramidal portion 12 and the inner wall 14 of the piston cylinder 13. But, with the frictional sliding of the piston 10 in the piston cylinder 13, the upper and lower pyramidal portions 12 on the wall 11 of the piston 10 will be gradually abraded, leading to expanded contact area due to the oblique cone surface of the wall 11 of piston 10. In such a case, the sliding behavior of piston 10 will be impeded due to the increasing friction coefficient, so insufficient suction will affect the performance of lotion pump, resulting in shorter service life.

Thus, to overcome the aforementioned problems of the prior art, it would be an advancement in the art to provide an improved structure that can significantly improve efficacy.

Therefore, the inventor has provided the present invention of practicability after deliberate design and evaluation based on years of experience in the production, development and design of related products.

BRIEF SUMMARY OF THE INVENTION

The enhanced efficacy of the present invention is as follows:

The circular rib 22 is made of ribs with predefined heights, being available with trapezoidal, semi-circular and pyramidal cross-sections. So, in the event of friction against inner wall 31 of the piston cylinder 30, the contact area will not expand greatly, avoiding unsmooth behavior of piston 20 and insufficient suction of lotion arising from the sliding of the piston. In particular, if there is little liquid in the vessel, it is possible to maintain smooth sliding of piston 20, leading to higher durability and improved applicability of the lotion pump.

Although the invention has been explained in relation to its preferred embodiment, it is to be understood that many other possible modifications and variations can be made without departing from the spirit and scope of the invention as hereinafter claimed.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 shows an assembled sectional view of a typical prior art structure.

FIG. 2 shows an enlarged sectional view of the prior art piston mechanism as disclosed in FIG. 1.

FIG. 3 shows an assembled sectional view of the preferred embodiment of the present invention.

FIG. 4 shows an enlarged sectional view of piston as disclosed in FIG. 3.

FIG. 5 shows a perspective view of piston mechanism of the present invention.

FIG. 6 shows a sectional view of piston mechanism of the present invention.

FIG. 7 shows a cross-sectional view of the application of the circular rib cross-section of the present invention.

FIG. 8 shows another cross-sectional view of the application of the circular rib cross-section of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The features and the advantages of the present invention will be more readily understood upon a thoughtful deliberation of the following detailed description of a preferred embodiment of the present invention with reference to the accompanying drawings.

Referring to FIG. 3, the piston tube 19 in the piston cylinder 30 protrudes from the extension hole 32 of the piston cylinder 30. A press head 15 of lateral discharge pipe 16 is assembled over the piston tube 19, while screwed portions 17, 18 are located opposite each other between the press head 15 and the extension hole 32. A spiral cap 34 is located between the piston cylinder 30 and circular shoulder 33, while the piston cylinder 30 is assembled onto the vessel mouth through the spiral cap 34. In addition, a piston 20 is assembled onto the piston tube 30, and a check valve 36 is placed in the tail tube 37 of the piston cylinder 30. A suction pipe 38 is extended from the tail tube 37 to the bottom, and elastic restoring members 35 are arranged within the piston cylinder 30 below the piston tube 19, enabling the piston tube 19 to suction the lotion through the reciprocating action of press head 15 and elastic restoring members 35.

FIGS. 3 and 4 depict preferred embodiments of improved piston mechanism of lotion pump A of the present invention. The embodiments are provided only for explanatory purposes.

The piston 20 is assembled into the piston cylinder 30 of lotion pump A in a sliding state. Through the ring surface 21, the piston 20 contacts the inner wall 31 of the piston cylinder 30. At least two circular ribs 22 are arranged at intervals on the ring surface 21. In the case of sliding contact between the circular rib 22 and inner wall 31 of the piston cylinder 30, its surface is allowed for friction with the inner wall 31 of the piston cylinder 30. Since the circular rib 22 is made of ribs with predefined heights, the contact area may not expand greatly, thus maintaining the smooth sliding of the piston. With the frictional sliding of the piston 20 in the piston cylinder 30, the surface of circular rib 22 and inner wall 31 of the piston cylinder 30 will be gradually abraded. However, the contact area of the circular rib 22 remains unchanged, so that the frictional area will prevent insufficient suction of lotion arising from the sliding of piston 20.

Referring to FIGS. 5 and 6, the piston is divided into inner ring 20A and outer ring 20B. The inner ring 20A and outer ring 20B are linked by a joint 23. The outer ring 20B is made of ring surface 21 and circular rib 22, enabling sliding friction between circular rib 22 and inner wall 31 of piston cylinder 30.

Referring to FIG. 7, the contact surface between circular rib 22A and inner wall 31 of the piston cylinder 30 has a trapezoidal cross-section. Referring also to FIG. 8, the circular rib 22B has a semi-circular cross-section. Referring also to FIG. 9, the circular rib 22C has a pyramidal cross-section. The major objective is to reduce the abrasion arising from the sliding contact with the inner wall 31 of the piston cylinder 30, avoiding change of the contact area. 

1. A piston mechanism of a lotion pump, comprising: a piston cylinder having a piston assembled in said piston cylinder, said piston being slideable within said piston cylinder, said piston being in contact with an inner wall of said piston cylinder through a ring surface; and at least two circular ribs arranged at intervals on said ring surface, enabling sliding contact between each circular rib and said inner wall of said piston cylinder.
 2. The piston mechanism defined in claim 1, wherein each circular rib is available with trapezoidal, semicircular and pyramidal cross-sections. 